Minor edits to testing Readme.
Removed Fibonacci and close_line testing examples.
Added TDD example using calculate_gc function.
Added another testing exercise using transcribe function.
Removed extra materials on testing, debugging, and softare engineering that are not being used for this boot camp.
Merge branch '2013-06-chicago' of https://github.com/swcarpentry/boot-camps into 2013-06-chicago